It’s about a week to apple firmware 2.2.1 for iPhone and iPod touch release. Soon after upgrading iPhone and iPod touch to firmware 2.2.1 many users started facing crash in iTunes while trying to sync iPhone and iPod touch.

Fortunately this iTunes crash has been traced to bug in firmware 2.2.1 and apple has provided a quick fix for this issue. The email fix for iTunes crash has been send out to all affected customer. Here is content of email send by apple.

Fix iTunes Crashes while iPhone and iPod Sync After Firmware 2.2.1 Upgrade

Dear Customer,

Recently, we uncovered an issue which was causing iTunes to unexpectedly quit when synced with an iPod or an iPhone. This issue impacted a small number of users, and we have identified your account as potentially being affected.

If you have experienced this issue, please follow these steps in order to sync your iPod or iPhone with iTunes:
1. Launch iTunes
2. Select “Deauthorize Computer” from the Store menu
3. Enter your iTunes Store Account ID and Password, then click the Deauthorize button
4. Next, choose “Authorize Computer” from the Store menu
5. Enter your iTunes Store Account ID and Password, then click the Authorize button

Once you have successfully deauthorized and reauthorized your computer, you should be able to sync your iPod or iPhone to iTunes.

I sincerely apologize for any inconvenience that you may have experienced as a result of this issue.

Thank you for being an iTunes Store customer.
iTunes Store Team

The fix provided with email seems to be working for most of affected users Some, however, have to take the additional step of “purchasing” a Free iTunes App after following the steps before syncing will work again.